The present invention relates to a culture water thermostat in a water tank for aquarium fish and a method of controlling culture water temperature, using a plurality of Peltier elements which cause exothermic and endothermic reaction when power is supplied. In addition, the present invention also relates to a method of controlling culture water temperature in a water tank, wherein in order to enlarge the surface area where peltier elements specifically assigned to increase or reduce temperature are in contact with fluid or air, the surface area of a flow pipe is expanded, and the heat exchange efficiency is enhanced using a plurality of heat sinks.
The basic principle of the present invention, the Peltier effect, found by J. C. A. Peltier in France in 1834, is a kind of electrical properties occurred by contact covered in electronics and materials engineering. When electric current is applied to two different materials in contact with each other, endothermic and exothermic effects are generated. The Peltier effect directs the property where heat is generated when a current flows in one direction, while heat is absorbed when the current flows in the other direction.
As an example of applying reversibility of the Peltier effect as seen above, a Peltier element made of N-type semiconductor element and P-type semiconductor element connected by a metal plate, is typical. This Peltier element is also called a thermoelectric device or thermoelectric module.
When supplying power to the Peltier element, an electric current flows to the N-type semiconductor element and then flows through a connecting metal plate and P-type semiconductor element, to thereby generating heat generation while generating heat absorption in the connecting metal plate. Meanwhile, when supplying power in the opposite direction, heat absorption occurs followed by heat generation.
In general, in addition to its heating and cooling functions, the Peltier element does not generate any pollutant in disposal due to its small size and noiselessness. Thus, it can be used for refrigeration equipments for storing cosmetics or pharmaceuticals where there is no need to reduce refrigeration temperature to a very low level; for a compact refrigeration unit which can be easily installed in a small space; and for a portable refrigerator using batteries as a power source.
In addition, a Peltier element is reliable and semi-permanently used since it has a solid structure. And more precise temperature control than .+−.0.05° C. (PID control) is possible with an installation of an appropriate control system since cooling is available to be lower than ambient temperature (environment temperature). Therefore, recently, technologies of applying a Peltier element to temperature controllers have been frequently developed.
However, the unit price is expensive, dropping its economic value, and it takes time to lower a temperature of a heating part to an appropriate level, since cooling efficiency of a heat absorption part depends on the temperature of the heating part reserving latent heat generated while heat absorption, dropping cooling efficiency by means of a Peltier element. On the other hand, since it takes time to raise a temperature of a heat absorption part to an appropriate level, dropping heating efficiency by means of a Peltier element, development of technologies which can improve the heat exchange efficiency is urgently needed.